The polyketide synthase StlA is involved in inducing aggregation in Polysphondylium violaceum.

Abstract

In the social amoeba Dictyostelium discoideum, the polyketide MPBD (4-methyl-5-pentylbenzene-1,3-diol) regulates the gene expressions of cAMP signaling to make cells aggregation-competent and also induces spore maturation. The polyketide synthase StlA is responsible for MPBD biosynthesis in D. discoideum and appears to be conserved throughout the major groups of the social amoeba (Dictyostelia). In this study, we analyzed the function of StlA in Polysphondylium violaceum by identifying the gene sequence and creating the knockout mutants. We found that Pv-stlA- mutants had defects only in cell aggregation but not in spore maturation, indicating that the function of StlA in inducing spore maturation is species-specific. We also found that MPBD could rescue the aggregation defect in Pv-stlA- mutants whereas the mutants normally exhibited chemotaxis to their chemoattractant, glorin. Our data suggest that StlA is involved in inducing aggregation in P. violaceum by acting on signaling pathways other than chemotaxis in P. violaceum.